News Health/Medical Increased Allergic Risk Post-COVID-19: A Multinational Study

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Increased Allergic Risk Post-COVID-19: A Multinational Study

By Dr. Liji Thomas, MD

Reviewed by Lily Ramsey, LLM

Published on April 3, 2024


The emergence of severe respiratory syndrome coronavirus 2 (SARS-CoV-2) in late 2019 led to the declaration of a coronavirus disease 2019 (COVID-19) pandemic in March 2020. The virus caused over seven million deaths and numerous infections and hospitalizations. Nearly half of COVID-19 cases experienced delayed or chronic morbidity, known as post-acute sequelae of COVID-19 (PASC) or long COVID. Some PASC symptoms include immunologic phenomena that may lead to various allergic conditions.

The Study

The study investigated how ethnicity influences allergic conditions following COVID-19. Researchers formed a synthetic group comprising over 22 million individuals from South Korea, Japan, and the UK. Participants represented diverse ethnic backgrounds. Specifically:

  • South Korean segment: Over 800,000 people with an average age of 48
  • UK cohort: Over 325,000 participants
  • Japan cohort: Over 2.5 million participants

Within these groups, approximately 150,000 participants from South Korea, 77,000 from the UK, and 542,000 from Japan had been infected with SARS-CoV-2. The large-scale analysis aimed to shed light on ethnic variations in post-COVID-19 allergic reactions.


After adjusting for relevant variables, the researchers found that individuals infected with SARS-CoV-2 had a 20% higher occurrence of allergic diseases compared to non-infected individuals. This increased risk was consistent for both the original and Delta variants of the virus. Specifically:

  • Asthma risk more than doubled in infected individuals.
  • Allergic rhinitis risk was 25% higher in the infected group.
  • No significant increase was observed for food allergies or atopic dermatitis.

Although the risk decreased over time after infection, it did not disappear entirely, varying by country.

Severity and Vaccination

Moderate-to-severe COVID-19 was linked to a 50% higher risk of overall allergy compared to mild disease. COVID-19 vaccination also influenced allergy risk:

  • One vaccine dose increased allergy risk by 44%.
  • Two vaccine doses reduced the risk by 20%.

These findings highlight the need for continued monitoring of allergic conditions in post-COVID-19 patients.

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